Killer Caterpillars!

Pine Processionary Caterpillars

Pine processionary caterpillar
Pine processionary caterpillar

The title may sound a little dramatic even OTT, but in truth these cute and harmless-looking caterpillars pose a real danger to people and pets.

Since moving to Portugal I have developed an unexplained desire to learn more about the insects I find in our garden. I like, no NEED, to know are they friend or foe!

When we first arrived in Portugal we noticed our neighbour had several cocoon like nests in his pine trees. We were soon to discover they were home to hundreds of caterpillars which when they descended from the nest, marched nose-to-tail in a procession along our garden wall until they disappeared into the soft soil. We were told they were called Pine Processioanry Caterpillars but little did we know then, how dangerous they were!

The silken cocoon nest of the Processionary Caterpillar
The silken cocoon nest of the Processionary Caterpillar

Please read on and you will understand why coming into contact with pine processionary caterpillars may have such terrible consequences.

Where are they found?
Pine processionary caterpillars are found in Southern Europe, anywhere there are pine trees.

The caterpillars live in silken spun cocoon nests attached to branches in the pine tree. These cocoons can accommodate hundreds of
caterpillars which once developed will descend from the nest in late winter/early spring. On leaving the nest they proceed nose-to-tail (like a procession) as they go in search of soft soil in which to burrow and pupate, before changing into harmless moths.

So why are they so dangerous?
The adult caterpillar is approximately 3cm long and covered in tiny brittle barbed hairs which are constantly being shed.
Because their hairs are airborne they may inadvertently be ingested simply by picking the caterpillar up, stepping on it or attempting to move them out-of-the-way.

Symptoms and what to do
The hairs, when they come into contact with the skin, can cause severe skin irritations and if ingested possibly even cause Anaphylaxic shock. If you do come into contact with these caterpillars and you develop an itchy rash, seek medical advice.
Seek medical advice immediately
Dogs and Cats
When dogs and cats get to close to the caterpillars they may pick up hairs in their paws which they then lick, and therefore ingest with potentially catastrophic consequences including death. The symptoms of ingestion may include swelling, vomiting and excessive drooling. Check for small white spots on the tongue and in the mouth.  If dogs or cats eat these caterpillars the consequences can be fatal so if your  pets come into contact with processionary caterpillars do seek veterinary advice immediately.
You need to contact your Vet urgently.Processionary caterpillars march nose-to-tail

Processionary caterpillars march nose-to-tail

Finally a few useful tips
Do not attempt to remove the nests as hairs may be released which may then come into contact with the skin or even ingested.
Do not burn the nests as hairs may be released into the air.
Do not attempt to move a procession of caterpillars as this will spread their hairs.
Do not allow dogs and cats near the nests or caterpillar Curiosity killed the cat.
Do contact your local Camara (local council) to see what their policy is regarding removal of nests, especially if they are in an urbanisation

If you do not have any luck with your local Camara I have been advised the treatment to get rid of the caterpillars/moths is Pheramone traps, glue bands, insecticidal spray, etc which you can obtain from Biosani.

My thanks to Paws2Claws Pet Boarding who has shared much of the above information and the great pictures
Have you seen these caterpillars?
Please share any information or actual personal experiences!

41 thoughts on “Killer Caterpillars!

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  1. My gardener had to shoot his dog after it bit the line of caterpillars.
    Call a specialist company as soon as they are seen, it is better to have the nests sprayed when they are in the trees.
    I did every year.


  2. Really enjoyed your informative article. we just had another warning here in spain about them again in the local news : “”

    I did not realize about the orange juice for helping one personally or about contacting the council to remove nests. Still timeless advice, thank you so much!!


  3. Our local vet will provide a kit that you can take out with you on walks with medicine in it to give your dog if they are affected by the caterpillars. It just helps give you time to get to the vet.


  4. Yeah well my mother already scared me enough and now i read this blog making me more paranoia…..
    Cause i have these critters in front of my house and own animals…

    But now information on how to combat these animals?

    Do there go down the tree during night and back up after feeding?

    I see some nest in a couple of trees, where can i find real info on how to combat them also on the website where you can buy pheromones etc it doesnt say at all what to do with the glue strips or traps .

    Thank you


  5. I just saw one today and nearly picked it up to show my husband. He stopped me just in time. Googled it and saw your advice about the killer caterpillars!


  6. I never thought about that next time we get bit by the mosquitos I will have to give it a try at the moment we find toothpaste the best thing and it has to be white toothpaste as the gel types don’t seem to work as well


  7. Hi last year our dog came into contact with this horrible little caterpillars she sniffed some in a bush on the ground with in about 5 minutes she was being very sick, we got her straight home phoned our vet who told us to rub fresh orange juice all around her face plus down her front legs and keep doing it and get her to the surgery asap. The vet gave her tablets plus a couple of injections and also got some more oranges to keep rubbing on her. After about 3hrs in the vets I’m glad to say she was ok her tongue had gone down and she had stopped being sick, we took her home with some more tablets to give her and had to take her back to the vets a couple of days later plus I had to text our vet 3 times a day to let her know how corky was doing. After all the corky is great no lasting damage which our vet told us was down to the orange juice, mind you corky doesn’t like anyone rubbing her face now lol. Also my partner got stung a few weeks ago while trying to get rid of a nest we rubbed an orange over it and all was good the pain went away instantly. I hope this helps some people and sorry it is so long.


  8. I am a retired lady in Spain I not knowing about these lilltle creatures swepted up with brush pain 3 rows of these within 2 days you can immagine iv been up for last 3 nights scratching most of my body covered with rashes. I also keep going dizzy. Think better go to doctor s tomorrow.


  9. Dear Mrs. Weinhold, we hope the very best for Your Lulu, and we understand fully your desperation and sorrow about her state!
    End of Januray our little, funny and vivid, intelligent , 9 years old dog Didi, a Tibetan Spaniel,beloved family member came in a pine wood north of Vila do Bispo unobserved obviously into contact with the poisonous caterpillars of the pine procession moth which had been thrown down to the ground by the storm. All the times bevore there had been no caterpillars in that wood!
    She came out of the wood quite slow, apathetical, white foam from her mouth. At home we did not know, how to handle (we should have washed out her mouth immediately with warm water!), and she was still feeling not good, apathetical and had a lot of pain, her tongue heavily swollen, and heavily breathing. So we went immediately to a veterinarian. They washed out her mouth, and hang her to an infusion with a vet cortison.They wanted to keep her for observation overnight, and we left in good hope, The next morning at 9:00 the verterinarian called that Didi was not doing well, and at 11:00 they told she was falling into coma and shortly after that the poor doggy died, after pieing blood, We suppose a death from kidney failure.
    All this happened as knowbody, even not our neighbours informed us on the lethal danger these “killer” caterpillars (in Portuguese: “processionaria”) represent to cats and especially dogs, sniffing curiously on the ground.
    So I informed myself , unhappily only after the dreadful death of our dog,
    in order to warn all pet holders in Portugal and Spain:
    These caterpillars appear during Winter times, and are especially poisonous in February when they have their 3rd larval development stage.
    They can eject their uricating poisonous, barbed hairs like harpoons as far as 3meters, and these hairs stay poisonous active on /in the ground for 3 years!
    Animals get the following reactions at contact e.g. with their tongue with
    the poison: dreadful pain and itch, allergic shock, drop of blood-pressure,
    swelling of tongue as welle as digestion and respiratory system, suffocation, apathetical behaviour, saliva and white foam from the mouth, asthmatic reation, coma, kidney failure, death. Due to necrotic reaction (fowling) even suviving larger dogs often loose half of their tongue and/or
    may keep a devastated face.
    First aid: washing the mouth of the pet with warm water, and quickly visiting the next veterinarian!
    The nettle poison thaumatopoein is also dangerous for humans as there occur: allergical shock, nausea, eye irritation by ophthalmia nodosa, contacturtoicaria, conjunctivitis, pharyngitis, bronchitis, fever, asthma, and a
    lot of later reactions!
    In Portugal caterpillar populations of the pine procession moth in private and municipal pine woods must be removed by law, but pine woods in nature reserves e.g. along the West coast are mostly not cleaned from this danger, and there are even no warning boards about it!
    So, knowing all about the lethal danger by the caterpillars,
    best keep away Your pets from any pine wood.
    This is to inform any pet holders in Portugal, tourists and residents helping them to save the health and the lives of their pets!
    This is a message from the very sad holders of beloved Didi which we hoped to go asleep normally by age later, and not experiencing such a dreadful death, in fact only caused by non-information and iignorance! Volker and Gitta Diersche


  10. Hi. We have been here just 3 weeks and today we found a procession of these caterpillars walking down our drive. Our Portuguese neighbour warned us about them. Thanks for your invaluable information. We are near Odemira in the Alentejo.


  11. I had already experienced this type of caterpillar in Southern France,but you can only image my sadness, when my lulu was suddenly vomiting and shaking yesterday night after being in the garden during the rare show of sunlight this week. Lulu started showing symptoms late last night, something kept niggling me when lulu left trails of vomit all over the house the spate of 10 mins. By the time we arrived at the vet she couldn’t control her bowls and was peeing blood. The vets weren’t too sure of what her problem was and suggested that we leave lulu there overnight and check on her next morning.

    Today I was informed that lulu had in fact been in contact with the pests and that her tongue has swollen up over night which is the main symptom. Horrified,devastated and gutted, not only does the hairs from this caterpillar cause death prior to this the animal will suffer excruciatingly. In the case of my lulu if her tongue starts to rot this could lead to her losing her entire tongue which without she will have to be put down as it her only manner of eating and drinking. I can even tell my children about the chance of lulu dying and hate been crying privately around the house. Lulu has been in our life for just under a year, she is my little joy, never asking anything other than to be taken out for walkies; all I can do is wait and pray.
    I hope that something can be done to avoid losses but for now I hope that my lulu can be saved


  12. Prednisolone is a prescription only mediction POM and should be used only under veterinary direction. Vets even gradually reduce the dose after a course rather than just immediately stop the drug. Do not give prednisolone to your pet if the pet has a serious bacterial, viral, or fungal infection. Prednisolone weakens a pet’s immune response and its ability to fight infections. Tell your veterinarian if your pet has kidney or liver disease, heart disease, stomach ulcers, hypothyroidism, diabetes mellitus, or any other medical conditions.


  13. Hello.
    Wanted to share my knowledge in the hope of being useful.
    I work in a Pine forest, and after long battling with these cute, lethal worms we discovered they don’t cross big salt lines. Try mixing glue with salt and painting over your walls, should keep them from going that way, plus, the mix is invisible once dry so it shouldn’t hurt your gardens ascetics.


  14. Saying that this creature is nasty is a lie.Up in the North{Portugal} i used to come across with them everyday,even as a little child.You scratch your legs,but it is good cures you from cancer,also they are funny when create meters upon meters in line from the nest to the next pine tree.


  15. For the most part, antihistamines are safe. Having said that, antihistamines can have side effects which, if the antihistamine is not properly administered, can be serious. The truth is, all medications have side effects. Some are mild, as in the case of an aspirin, unless you have stomach ulcers or aspirin sensitivity and others are more serious such as the side effects from chemotherapy, but for the most part, antihistamine side effects are fairly mild. The newest antihistamines are probably about the safest medications that there are. But there are differences between the various antihistamines and their side effects.,

    Our new blog


  16. Brilliant post, Pip. Our family live near Porto, do these bugs occur up north?
    BIL has never mentioned them before?


  17. Just read this and wanted to thank you for sharing information I hope never to need! But living on the edge of a forest, with a dog, there’s unfortunately always a chance that I might. I’d heard of these nasty critters and how harmful they can be but wouldn’t have known what to do about them. I do now!


  18. Re caterpillars, we have small brown caterpillars on the patio they have spikes with orange tips and on closer inspection short tufts out of the orange tip. They are singular not in a line and have noticed them over the last week. Can anyone shed any light on these creatures please.


  19. Hi Val,
    Information from people with personal experience of the problems these caterpillars can cause both to pets and humans is invaluable and far better than theory 🙂 Thanks for your help!

    Kind regards


  20. Hi Pip,

    Glad we could help with your research and it is great that you are bringing this to peoples’ attention; a lot of expats in Portugal don’t seem to realise they exist!

    When we decided to continue our successful pet boarding in this part of Portugal we wanted to buy a house deep in the heart of the country. We found our dream home but one downfall was that this was on the edge of a lovely mixed forest with some pine trees and have spent the last few years eradicating these beasties completely, but continue to take precautions. This is the company to buy from if your Camera or local Cooperativa Agricola can’t assist. You need a Pheramone trap, Pheramone capsules, Glue Bands and Turex insecticide spray. If anyone wants any further info, drop us a line. Details can be found here (they do reply to emails and speak English):

    Good Luck with your Blog Pip, it really is very enjoyable to read! Best wishes Val


    1. Hi,

      I lool on there website, but what do you exactly do with the glue traps? You put it around the treetrunk?
      And the other traps or insectice how do you ise it and when etc.

      I saw these thins walking infront of my door and see some nest in front of my house, but real info on how to combat them i havent been able to find.

      Thank you


  21. Hello. I´m Portuguese, from Lisbon. I have been reading your blog for some time now…thank you for all the messages.
    This time I have my own story about this insect, Processionaria, how we call it in Portuguese. well when I was a little boy back in the 80´s my father brought us a pine tree branch as our Christmas tree for that year. We were all very happy at our living room decorating the tree when all of a sudden my mother said that she had her hand burning because she had taken a fur ball (the nest) from one branch of the tree. I can´t remember if there was actually any animal there. The Only think I know was that my father said “É da lagarta do pinheiro” (it´s the caterpillar) and he took everything from the tree all off a sudden and went out and put fire to the tree. A very sad story for the Christmas ahead lol 🙂 but sure was a lesson. Thank you!


    1. Hi Jaime,
      Thanks for sharing your story! Your poor Mother must have been in a lot of pain 😦 There are so many newcomers to Portugal who are not even aware of the hazards these caterpillars pose! In this case ignorance is not bliss…



    1. Hi LW,

      Yes, they are quite scary but OK if you respect them and give them a wide berth. Holiday makers/golfers need to be aware of these, as you say wee beasties, especially if they go for walks in the pine forests at certain times of the year.



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